This proposal seeks to study weight maintenance behaviors, weight trends and behavorial differences between healthy, normal weight (+-15 percent IBW) and mildly obese (greater than 20 percent but less than 40 percent IBW) adults retrospectively by history and prospectively over 5 years. Effects on overall health, particularly cardiovascular disease risk (CVD), will be assessed and the characterization of behaviors to formulate predictive models on which to build future interventions will be emphasized. A 2 x 2 x 5, multifactorial design will be used where sex (males vs. females) and weight (obese vs. normal) will be crossed with 5 different age groups according to decades (20-29, 30-39, 40-49, 50-59 and 60+ years), respectively. A longitudinal, process-analysis approach will be utilized where 500 subjects will be studied in their natural setting and followed yearly for 5 years. The selection of subjects will be biased toward the working class (faculty, employees, students and their spouses/friends) reportedly in good health (less than 1 sick day/month for the last year), who will be paid for their participation in the study. A total of 50 (25 normal + 25 obese) will be recruited for each age/sex group. Dependent variables will be: 1) weight (weight trends, fluctuations, interrelationships, body composition); 2) diet (adequacy, eating patterns, caloric balance, varability in nutrient intake, validity of self-reports); 3) activity/exercise (frequency, duration, type, patterns, caloric equivalents, behavioral correlates); 4) behaviors, (weight maintenance, weight gain/loss, adaptive responses); 5) general well-being (days sick and days missed from work, psychopathology (SCL-90R), emotional states (GWB, CES-D), locus of control (Levenson) and routine blood and urinalyses; and 6) CVD risk (lipid profile, BP, 24-hour urinary Na, K, Ca and P, diet, and changes in medical status/medication use). The major data analyses will employ repeated measures, multiple analysis of variance and covariance. Emphasis will also be placed on descriptive analyses and correlational statistics. Overall, this study will provide valuable information regarding behavioral correlates and strategies used for weight maintenance in the prevention of obesity in normal weight individuals and identify strategies which might be successful in the prevention of the progressive escalation and/or extreme fluctuations in weight in the obese state. Medical, nutritional and psychological consequences will also be identified and methodology to be used in future studies will be validated.